(Lianja) Check Internet Connectivity

Demonstrates an efficient way to test for Internet connectivity.

Chilkat Lianja Extension Download Chilkat Lianja Extension

llSuccess = .F.

loSocket = createobject("CkSocket")
// 1. Use a reliable Anycast IP. 
//    8.8.8.8 (Google) or 1.1.1.1 (Cloudflare) are the industry standards.
lcTargetIp = "8.8.8.8"

// 2. Use Port 53 (DNS). 
//    DNS servers typically listen on TCP Port 53 as well as UDP. 
//    (Alternatively, use port 443 if you suspect port 53 is blocked).
lnPort = 53

// 3. Disable SSL (0). 
//    We are not doing a handshake, just a TCP connection.
llSsl = .F.

// 4. Short Timeout (1500ms).
//    If you can't reach Google in 1.5 seconds, the connection is 
//    likely too poor for practical use anyway.
lnTimeoutMs = 1500

// Connect
llSuccess = loSocket.Connect(lcTargetIp,lnPort,llSsl,lnTimeoutMs)
if (llSuccess = .F.) then
    ? loSocket.LastErrorText
    release loSocket
    return
endif

loSocket.Close(10)

? "We have Internet connectivity."


release loSocket